Solera aging is a method most commonly used in making sherry and vinegar, but occasionally beer and wine employ it as well. Cyclically liquid is removed from the aging vessel (most often a barrel) for consumption, this vessel is then topped off with fresh liquid and allowed to age further. This process is repeated indefinitely. This spreadsheet ( SoleraAgingNew.xls ) calculates the average age of the portion removed from a single vessel solera. To use it enter information in the yellow boxes on the right side of the sheet, the table on the left will populate with the average age (in years) of the blend for each pull. The new second tab allows you to calculate a multi-vessel solera where liquid is taken from each barrel in series and added to the next.